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Last reviewed 2026-10-20

Radon in Pennsylvania: Results by ZIP, Rules and Cost

Of 2,644,039 basement radon tests reported to the Pennsylvania Department of Environmental Protection from July 1985 through July 2026, 37.3% read at or above EPA's 4 pCi/L action level, according to our count of the DEP's public test-results data set. That is far above the roughly 1 in 15 homes EPA estimates for the country as a whole (EPA Citizen's Guide to Radon, 2016).

EPA's 1993 Map of Radon Zones puts 49 of Pennsylvania's 67 counties in Zone 1, the highest-potential band, where the predicted average indoor screening level is above 4 pCi/L. A typical active soil depressurization system costs $1,200 to $2,000 installed nationally (HomeGuide, Feb 2026), and in Pennsylvania the installer must hold DEP certification under 25 Pa. Code Chapter 240.

Pennsylvania is the one state where the public data is fine-grained enough for a true ZIP-code view. The radon levels by ZIP tool shows DEP basement-test results for 1,452 Pennsylvania ZIP codes that have at least 30 tests, alongside the EPA zone of the county each ZIP mostly falls in.

Licensing and permits

Certification: Pennsylvania requires DEP certification before anyone tests for radon or installs a mitigation system for a fee. Individuals need an approved course, a passed exam and qualifying experience (25 Pa. Code §240.111–240.112), and firms need a certified responsible individual.

Reporting: certified mitigators report installations and post-mitigation results to DEP (25 Pa. Code Chapter 240, Subchapter D). Ask your installer for the DEP certification number and keep the post-mitigation test with the house records.

Local permits: some municipalities require an electrical or building permit for the fan circuit and roof penetration. HomeGuide reports radon system permits at $25 to $150 nationally, and most contractors include them in the bid.

Real estate: radon tests are common during Pennsylvania home sales. Use a DEP-certified tester so the result holds up in negotiations.

Who to call: DEP's Bureau of Radiation Protection Radon Division certifies testers and mitigators, EPA sets the 4 pCi/L action level, and your municipality's Uniform Construction Code office handles any building permit an install needs (Pennsylvania DEP; US EPA).

Local conditions

Geology drives the pattern. The highest county shares in the DEP data sit in the central Ridge and Valley and the south-central counties: Fulton (66.3% of 879 tests at or above 4 pCi/L), Juniata (59.5% of 2,056), Perry (57.7% of 7,069), Mifflin (56.7% of 4,907), Lebanon (55.7% of 33,304) and Centre (53.6% of 48,355), counting all floor levels.

Large metro ZIPs can differ sharply. Basement tests in ZIP 16801 (State College) were 55.0% at or above 4 pCi/L across 14,691 tests, and 17402 (York) 59.8% across 8,558, while 19148 in South Philadelphia was 4.2% across 7,400 (PA DEP data, our count).

Housing: most homes in central Pennsylvania have basements or block foundations, the setup where sub-slab and block-wall depressurization are common. Block-wall systems cost $1,800 to $3,000 nationally (HomeGuide).

What drives local prices

  • Foundation type across Pennsylvania: a poured basement usually takes sub-slab suction at $1,200 to $2,000, while hollow block walls often need block-wall depressurization at $1,800 to $3,000, based on HomeGuide's published Feb 2026 ranges.
  • Number of suction points: tight or wet sub-slab fill needs more (EPA Consumer's Guide); our calculator adds an est. $250 to $500 per extra point.
  • Pipe route: exterior runs cost less than interior or attic runs, an est. ×1.15 in our calculator, common in rowhouse neighborhoods in the state's older cities.
  • Starting level: very high readings, common in Ridge and Valley counties in the DEP data, can need a stronger fan or extra points.
  • Permit and retest: $25 to $150 for a permit where a municipality requires one, and $125 to $400 for a professional post-mitigation test (HomeGuide).
  • Certification overhead: Pennsylvania's DEP certification and reporting add to installer costs compared with unregulated states (est.).

Common jobs

  • Sub-slab depressurization for a basement home: $1,200 to $2,000 installed nationally (HomeGuide, Feb 2026).
  • Block-wall depressurization for hollow block foundations: $1,800 to $3,000 (HomeGuide).
  • Drain-tile suction where a perimeter drain exists: $900 to $1,800 (HomeGuide).
  • Fan added to a passive system in a newer home: about $300 in EPA's 2010 Consumer's Guide (2010 dollars).
  • Post-mitigation test by a certified tester: HomeGuide lists $125 to $400 for a professional test or $10 to $30 for a kit.

From test to fixed, and where we cover

County radon pages cover seven Pennsylvania counties so far: York, Lebanon, Centre, Adams, Snyder, Chester and Washington. Each uses DEP basement-test results for the ZIP codes centered in that county.

For every other part of the state, the radon levels by ZIP tool shows DEP results for any Pennsylvania ZIP with at least 30 basement tests. The quote form routes Pennsylvania requests to DEP-certified mitigators only.

Step 1: test the lowest lived-in level. Step 2: if it reads 4 pCi/L or higher, get two bids from DEP-certified mitigators. Step 3: compare each bid with the radon mitigation cost calculator. Step 4: retest after installation and keep the DEP-reported result.

Communities: Harrisburg, State College, York, Lancaster, Lebanon, Reading, Allentown, Altoona, Pittsburgh, Philadelphia

Questions about Pennsylvania

What percentage of Pennsylvania homes have high radon?

In DEP's public data, 37.3% of 2,644,039 basement tests read 4 pCi/L or higher (1985 to 2026, our count). Tests are voluntary, so homes that suspect radon are over-represented.

Which Pennsylvania counties have the highest radon?

By share of tests at or above 4 pCi/L in DEP data: Fulton, Juniata, Perry, Mifflin, Lebanon and Centre, all above 53%.

Does my Pennsylvania mitigator need a license?

Yes. Radon testers and mitigators must be certified by DEP under 25 Pa. Code Chapter 240. Ask for the certification number before signing.

How much does radon mitigation cost in Pennsylvania?

No state agency publishes prices. National survey data puts a standard system at $1,200 to $2,000 (HomeGuide, Feb 2026); block-wall homes run $1,800 to $3,000. Use the calculator and get two DEP-certified bids.

Can I see radon results for my Pennsylvania ZIP code?

Yes, for 1,452 ZIPs with at least 30 basement tests in DEP data. Use the radon levels by ZIP tool; a ZIP average never replaces testing your own home (EPA).

Sources

County radon guides in Pennsylvania

Rules and fees change; confirm with the state radon office. Price your own system with the radon mitigation cost calculator, read the radon mitigation cost guide, or check any ZIP with the radon levels by ZIP tool.

Other radon guides

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Tell us about your home and your test result. Cornelia Cove LLC reads every request and replies by email; we share it with a certified or licensed mitigator only if you ask us to. Your details are never sold to data brokers.

Bring your test result and the calculator range. A fair bid itemizes the system, suction points, fan and warranty, pipe route, sealing, permit and retest.